Asia has been experiencing rapid industrialization, urbanization, and economic growth in recent decades. Taiwan was one of the 4 Asian dragons, regions that experienced rapid industrialization and exceptionally high growth rates between the early 1960s and 1990s, but at a high cost to the environment, and thus, it was heavily polluted. Estuaries are highly dynamic and diverse ecosystems that provide multiple ecosystem services that maintain marine ecosystem health and benefit humankind. However, estuaries and the ecosystem services they provide are rapidly degrading due to increasing pressures and changes, especially those in populous, urban areas. Social–environmental analysis integrates scientific information and social activities and thereby provides a comprehensive understanding for the multiparty, joint decision-making processes necessary for successful, sustainable management. In this study, 60 years of economic data and 26 years of water quality data are examined using social–environmental frameworks, the driver-pressure-state-impact-response framework, and the systems approach framework to analyze the management of water quality for an estuary in a populous urban area, the Tamsui River estuary, in Taiwan. Potential societal responses and management measures are identified that can be implemented to reduce human activities, diminish pressure, ameliorate water quality, and enhance the state of the estuarine systems in the Tamsui River and its estuary. The recommended societal responses are increased education, the establishment of community-based river rangers, wetland and mangrove conservation, the development of a circular economy, the implementation of governance measures, and improvements in monitoring and assessments. Improvement of the water quality in the Tamsui River estuary increases the hedonic value of property for people who live near the riverside. Currently, the number of tourists and tourism-based businesses have increased. Nevertheless, improvements in water quality in the Tamsui River estuary bring well-being and benefits that could be further enhanced to increase the cost/benefit relation of the management measures.
